自動車破砕残渣 (ASR) の資源化・処理方式に関する4つのシナリオ (埋立, 焼却+埋立, 溶融+埋立, 溶融+山元還元) を対象にライフサイクルアセスメント (LCA) を行った. 影響領域としては, 地球温暖化, 酸性化, 有害化学物質 (人間毒性), 生態毒性, 廃棄物 (埋立地消費) を取り上げ, ASRの溶融処理試験結果で得られたインベントリーデータを中心に, LIME (日本版被害算定型環境影響評価手法) の更新版, LIME2が提供する各種評価係数等を活用して評価した. 溶融は埋立や焼却に比べて温室効果ガスの排出が多いものの, 重金属類等の排出による人間健康影響が少ないことと埋立地を削減できる効果がこれを上回った. さらに生態系への影響 (生物多様性) を考慮すると, その差は大きくなった. 溶融の中では, 溶融飛灰の山元還元 (資源化) の実施による重金属類の排出抑制効果が, 評価に大きく寄与することが示された.A comparative study of ASR treatment and recycling was conducted to evaluate the impact of four scenarios : landfilling, incineration followed by landfilling, melting followed by landfilling and melting followed by heavy metal recovery. Considering global warming, acidification, hazardous chemical substances (human toxicity), eco-toxicity and waste volume (landfill space occupied) as impact categories, the life cycle impact of each scenario was assessed based on an inventory of data obtained from the melting treatment of ASR and other processes and by making use of evaluation coefficients given in LIME2, which is a new version of LIME (Life cycle Impact assessment Method based on Endpoint modeling). Melting had the demerit of emitting more greenhouse gas than landfilling or incineration, but its merits of causing less damage to human health due to its smaller discharge of heavy metals and of requiring less space for landfilling outweighed this demerit. The difference between the merits and the demerit was larger when their effects on the ecosystem (biological diversity) were considered. It was found that the heavy metal recovery of fly ash in the melting process had a significant impact on the suppression of heavy metal discharge.